Chapter 12 – the heart 4 chambers – which act as 2 pumps for pulmonary circulation and systemic circulation 4 chambers – which act as 2 pumps for pulmonary circulation and systemic circulation See diagrams pp See diagrams pp Location – thoracic cavity between the lungs, within the mediastinum Location – thoracic cavity between the lungs, within the mediastinum Apex – most inferior portion Apex – most inferior portion Base – superior portion Base – superior portion

Heart anatomy diagram diagram

Go here for the best diagrams all kinds of wonderful information on the heart! all kinds of wonderful information on the heart! all kinds of wonderful information on the heart! all kinds of wonderful information on the heart!

External anatomy Coronary sulcus Coronary sulcus Superior and inferior vena cava Superior and inferior vena cava Pulmonary veins Pulmonary veins Pulmonary trunk Pulmonary trunk Aorta Aorta Membranes: pericardial cavity, pericardium: fibrous, serous, parietal, visceral, pericardial fluid Membranes: pericardial cavity, pericardium: fibrous, serous, parietal, visceral, pericardial fluid

Blood supply to the heart Coronary arteries (left and right) Coronary arteries (left and right) Cardiac veins Cardiac veins Coronary sinus Coronary sinus

Heart chambers Atria – right and left Atria – right and left Auricle Auricle Interatrial septum Interatrial septum Ventricles – right and left Ventricles – right and left Interventricular septum Interventricular septum

Heart valves Atrioventricular valves Atrioventricular valves Tricuspid valve – between right atrium and right ventricle Tricuspid valve – between right atrium and right ventricle Bicuspid (mitral) valve – between left atrium and laft ventricle Bicuspid (mitral) valve – between left atrium and laft ventricle Papillary muscles Papillary muscles Chordae tendineae Chordae tendineae Aortic and pulmonary semilunar valves Aortic and pulmonary semilunar valves

Blood flow through the heart Both atria contract at the same time and both ventricles contract at the same time Both atria contract at the same time and both ventricles contract at the same time Body  vena cava  right atrium  tricuspid valve  right ventricle  pulmonary semilunar valve  pulmonary arteries  lungs  pulmonary veins  left atrium  bicuspid valve  left ventricle  aortic semilunar valve  aorta  body Body  vena cava  right atrium  tricuspid valve  right ventricle  pulmonary semilunar valve  pulmonary arteries  lungs  pulmonary veins  left atrium  bicuspid valve  left ventricle  aortic semilunar valve  aorta  body

Heart wall Three layers: Three layers: Epicardium Epicardium Myocardium Myocardium endocardium endocardium

Cardiac muscle Striated Striated Elongated, branching cells Elongated, branching cells 1 or 2 nuclei 1 or 2 nuclei Rich in mitochondria Rich in mitochondria ATP ATP Intercalated disks Intercalated disks

Conduction system of the heart SA node SA node AV node AV node AV bundle AV bundle Left and right bundle branches Left and right bundle branches Purkinje fibers Purkinje fibers See diagram pg. 336 See diagram pg. 336 Ectopic beat Ectopic beat

electrocardiogram P wave P wave QRS complex QRS complex T wave T wave P-Q interval P-Q interval P-R interval P-R interval Q-T interval Q-T interval

electrocardiogram

Cardiac cycle Systole – atrial and ventricular – contraction Systole – atrial and ventricular – contraction Diastole – atrial and ventricular – relaxation Diastole – atrial and ventricular – relaxation Heart sounds – stethoscope Heart sounds – stethoscope Murmurs Murmurs Incompetent valve Incompetent valve Stenosed opening Stenosed opening

Regulation of heart function Cardiac output Cardiac output Stroke volume Stroke volume Heart rate Heart rate Cardiac output = stroke volume x heart rate Cardiac output = stroke volume x heart rate

Intrinsic regulation Regulation mechanisms contained within the heart Regulation mechanisms contained within the heart Venous return Venous return Preload Preload Starling’s law of the heart Starling’s law of the heart afterload afterload

Extrinsic regulation Regulation by factors outside the heart – nervous and hormonal regulation Regulation by factors outside the heart – nervous and hormonal regulation Baroreceptor reflex Baroreceptor reflex Medulla oblongata – cardioregulatory center Medulla oblongata – cardioregulatory center